Journal of Applied Physiology, Vol 78, Issue 1 76-81, Copyright © 1995 by American Physiological Society

ARTICLES

Exercise training attenuates the reduction in myocardial GLUT-4 in diabetic rats

J. L. Hall, W. L. Sexton and W. C. Stanley
Section of Cardiovascular Pharmacology, Syntex Discovery Research, Palo Alto 94303.

The purpose of this study was to determine the interactive effects of 10-12 wk of streptozotocin-induced diabetes (65 mg/kg) and moderate-intensity exercise training on total myocardial GLUT-4 and GLUT-1 proteins. Sprague-Dawley rats (n = 52) were randomly divided into sedentary control (SC), exercise-trained control (ETC), sedentary diabetic (SD), and exercise-trained control (ETD) groups. Diabetes (SD), and exercise-trained diabetic (ETD) groups. Diabetes resulted in a 70% reduction in myocardial GLUT-4 (28.3+/- 3.1 and 94.6 +/- 3.4% for SD and SC, respectively; P < 0.0001) and an 18.5% decrease in GLUT-1 (62.5 +/- 4.7 and 76.8 +/- 4.5% for SD and SC, respectively; P = 0.06). Exercise training increased citrate synthase activity in the medial and long heads of the triceps brachii in both groups (P < 0.001). Fasting blood glucose improved with training in diabetic animals (348 +/- 27 and 569 +/- 28 mg/dl for ETD and SD, respectively; P < 0.05). The diabetes-induced reduction in GLUT-4 was attenuated with exercise training (46.8 +/- 9.3% for ETD; P < 0.02 compared with SD). In contrast, training resulted in a further 25% decrease compared with SD in GLUT-1 in ETD (46.8 +/- 9.3%; P < 0.03 compared with SD). Exercise training had no effect on either GLUT-4 (87.2 +/- 4.0%) or GLUT-1 (75.4 +/- 5.1%) in ETC. GLUT-4 inversely correlated (r = -0.81; P < or = 0.001) with fasting blood glucose. In conclusion, diabetes resulted in a 70% reduction in myocardial GLUT-4 and an 18% decrease in GLUT-1.(ABSTRACT TRUNCATED AT 250 WORDS)

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